The Impact of Extreme Groundwater Recharge and Dewatering Events on the Efficiency of a Deep Anchored Wall

Abstract

The main objective of the present study is to evaluate possible changes in the efficiency of a deep excavation anchored wall after the excavation had been recharged for about two years. Extensive instrumentation monitoring was carried out to assess ground movements, groundwater levels, and the displacement of adjacent structures during the process of construction. Because of uncontrolled water seepage in one of the critical excavation wall, shallow pressure relief drains were installed in the wall base in the approximately deepest parts of the excavation. This was done to limit the uplift pressures and control the displacement and stability of the wall. Careful monitoring of the adjacent building and ground movement, especially in soft ground, gives confidence to contractors and designers to predict the effects of groundwater drawdown required for constructing large and/or deep excavations and controlling uplift pressures during construction. The findings of this study may offer some recommendations for the selection of methods of groundwater dewatering control when there is seepage through the excavation wall.